tree frog, name for any of the small tree- or shrub-inhabiting frogs of the family Hylidae, characterized by an adhesive disk on the tip of each of the clawlike toes. This family has about 300 species distributed throughout most tropical and temperate regions, with the greatest number found in the New World tropics. Tree frogs, sometimes called tree toads, are usually under 3 in. (7.5 cm) long. They are gray, green, or brown, often blending with the natural background; in most species the color varies with the temperature and other conditions. Most tree frogs lay their eggs in or near water, where the tadpole develops. Many species, such as the spring peeper ( Hyla gratiosa ) and the chorus frogs ( Pseudacris species), are known for the song they produce when they gather near ponds to breed in the spring. In one group of tree frogs the eggs are carried in a mass on the back of the female, exposed or in a pouch of skin. The tadpoles either are deposited in the water or continue their development in the pouch. A few members of the family, such as the North American cricket frog ( Acris crepitans ), are not arboreal. Tree frogs are classified in the phylum Chordata, subphylum Vertebrata, class Amphibia, order Anura, family Hylidae.